Battery Light on

Hi,
I have a 2014 Tacoma Sport TRD with about 114,000 miles and the battery light came on when I started it up one day and hasn't gone off since, over a week ago and haven't driven it much since. I checked the battery connections, cleaned, looked at the alternator for corrosion on the connections and even traced the battery terminal into the fuse box and everything looks solid.

I took it to autozone and had them test the battery and alternator and that came back within their specs, they had be rev the car up the 2.5K RPM for some load, I forget the numbers that chatted back to me. I also took a multi meter up to the battery ( which is only about 3 years old) and it registered 12.6, revved it, put the radio, lights, windshield wipers on, seemed good. Last night for an additional test I swapped the battery from my wifes care and stuck it in my truck and started it for a few minutes and the batter light stayed on.


I can just got out and buy an alternator and install it, probably going to be a pain in the ass how tight things are, but wanted to see if anyone else has any ideas before I do that. I tried to do a search on the forums and didn't really see to much more on this subject other then what I have already stated.

Any assistance would be appreciated. Thanks
Joe

 

12.6 volts is to low if the engine is running it should be in the 14-14.2 range. It will run on the battery but will not charge it.

 

Thanks for the quick reply, I could be wrong with my numbers when I started it.. I will double check, I know the battery was in spec when I tested it, and then put my wife's battery in...

 

It will be in the 14.x range if the engine is cold. Once fully warmed up it's not at all unusual for it to be at 13.4. These measurements are taken with the engine idling - transmission selector in Park and all accessories off.

 

battery light means there is a charging system problem - probably time for a new alternator

 

You are running the right tests.
The battery key off and min is 12.6. Start the Tacoma and at idle check again and voltage should be higher than when off as said above. Increase rpms up to 2000 and turn on AC, blower, access and voltage should not be less than the 12.6 (or what was measured off). If less alternator replacement time - but the auto store should have seen that. Check the main lead on the alternator and the plug in connector also. Been doing any work lately on the front area of the engine- pulleys, belt, hoses, AC work, ps hose? You can also pull the belt off alternator and spin the alternator and listen for grinding and feel for wear or wobble.

 

https://batteryuniversity.com/learn/article/charging_the_lead_acid_battery

you should read close to 14v at 2k rpm with all accessories and lights on.

 

Kudos OP for pulling out the multimeter!! in my opinion, that is the best first step.

 

I would have the alternator tested by someone else before you just go out and buy another.

 

This may help the charge LED is what you are calling the Battery Light. Since you have ruled out the battery the issue is with the regulator (which is built into the alternator) or the wiring between the alternator and the LED.

I would vote that the Alternator/Regulator is the most likely culprit.

I would also go with an OEM alternator over a crappy auto parts store rebuild. Unless you just like replacing them on a regular basis.

 

130A Denso from Carid $117. Free core return postage also. Your best option.

 

Thanks for all this information to each of you, I am going to replace the alternator as when I did another battery test all the numbers checked out. I wouldn't mind going OEM but damn they are so expensive, I have always had good results with Bosch, anyone suggest another good brand? I have no intentions about being cheap about but OEM is over priced.

 

Denso is OEM. Toyota has no new Denso alternators so they sell you a Denso rebuilt at 3x the Carid price for same alternator.

Info from Sep 2019 when I looked at alternators for 2005-2013 with tow (130A):
1. Only Toyota remanufactured replaces all internals such as rectifier and voltage regulator at about $300 plus your core #27060-0P020-84 . New ones are hard to find as no castings made still and #27060-0P020 at $385 and up new but good luck finding one.
2. AZ has New Duralast Gold at $231.99 lifetime and remanufactured at $163.99 plus core $45 lifetime.
3. Advance has CARQUEST reman at $163.99 plus 35 core limited lifetime and a Denso reman at $224.11 plus 65 core only 1 year warranty.
4. NAPA has Bosch reman at $175.99 plus 89 core with 2 year warranty and a Denso reman $203 plus 85 core 1 year.
5. O'Reillys has Ultimate reman at $167.99 plus 35 core limited lifetime.
6. Amazon has a ton of who knows ones New but good luck no real names or ratings I saw.
7. Carid has Denso reman $117.54 plus 79 core 1 year, AC Delco reman $183.71 plus 62 core 2 year, and New AC Delco add a pulley at $300 no core 2 year.
8. Rock Auto has a bunch, Denso reman $126.99 plus 84 core 1 year #210-0572, the AC Delco reman at $180.79 plus 62 core 2 year #3342691A, New AC Delco at $290.89 no core 2 year #3351302, then a New Remy at $200.79 #94752 and Remy reman at 82.79 plus 60 core #12453 (I have no info on the REMYs quality).

 

I have had good luck with local alternator shops rebuilding the OEM ones. Usually take it to them in the morning and they have it ready that afternoon. 9/10 times it is just the brushes that need replaced.

 

I purchased the DENSO 130A reman. alternator from Rockauto, twice, both times they were defective, had to send them back. It really surprised me. Instead I wound up going with a Delco-Remy reman. alternator. Working great now. I'd say 13 years and 400,000 miles on the orig. Denso alternator was a pretty good stretch.

 

Did you ever get around 14v on your multimeter with the engine running? If you did the problem isn’t the alternator, and more likely a sensing circuit issue.

 

hmm, I got 13.9, so when you mean sensing circuit, is that built into the alternator possibly?

 

Not an automotive tech, but looking at the diagram posted earlier it’s likely the M connection at the alternator Going back to the Engine Control module line. I would check all connectors at the alternator and make sure they are secure, and also at the BCM. If not the problem there I’d head to a dealer or a shop that knows Tacoma electrical for diagnostic.

 

Actually, your best replacement option is Napa. You will pay more but the quality is much better. Do not buy from other parts places (Autozone, Advance, etc.) they are all junk and you will be replacing the alternator quickly.

 

Napa is good stuff. Your Battery may have a bad or failing cell inside as well... don't rule that out.